Hardeners for photographic gelatin emulsions



States atent 3,542,558 Patented Nov. 24, 1970 U.S. Cl. 96-111 13 Claims ABSTRACT OF THE DISCLOSURE Bis(alpha carbonyloxyalkyl quaternary nitrogen) salts and polymeric analogs thereof are useful for hardening photographic compositions, such as gelatin compositions. The hardener compounds and the compositions containing them are believed to be novel.

This application is a division of our copending application Ser. No. 369,629, filed May 22, 1964, now U.S. Pat. 3,396,127, issued Aug. 6, 1968.

This invention relates to certain compounds found useful as photographic hardeners and to gelatin compositions containing those hardeners.

Some compounds which have been suggested as hardeners for photographic emulsions or other gelatin solutions have been insufliciently effective for that purpose.

One object of our invention is to provide hardeners for photographic gelatin. Another object of our invention is to provide gelatin compositions useful photographically. A further object of our invention is to provide certain compounds which are useful in the preparation of photographic products. Other objects of our invention will appear herein.

We have found that certain quaternary nitrogen type compounds, which compounds are free of deleterious photographic effects, are useful for hardening photographic emulsions or gelatin compositions generally. We have found that bis(alpha-carbonyloxyalkyl quaternary nitrogen) salts and polymeric analogs thereof are useful for hardening purposes in photographic compositions. These hardeners are not only useful in gelatin compositions but also have been found to be eifective for hardening polymers containing hydroxyl groups generally when incorporated in compositions thereof prior to coating out onto a support. We have found that several of the compounds in accordance with our invention, in addition to having a hardening eflfect on gelatin-silver halide photographic emulsions, also exert a sensitizing eifect thereon.

The compounds of our invention are conveniently prepared by the alkylation of the appropriate tertiary amine with an appropriate bis(alpha-chloroalkyl carboxylate). In lieu thereof these compounds may be prepared by the direct condensation of acid halide, aldehyde and tertiary amine by the procedure described by Iakubovich et al., J. Gen. Chem. U.S.S.R. Engl. Transl. 28, 1971 (1958). Compounds which have been found to be useful for hardening gelatin or some other polymeric material having carboxy] groups therein have the following general structural formula:

in which X is an acid anion such as halide, perchlorate or other suitable acid anion; R is hydrogen or a lower alkyl radical such as of 1-4 carbon atoms and B+ is a quaternary nitrogen residue from one of the following bases: (1) pyridine or simple derivatives thereof as for example picolines, Z-benzylpyridine, 2-(4-pyridyl)ethanol and the like, (2) a compound with a tertiary nitrogen in a bridgehead position as for example quinuclidine, (3) an aliphatic or cyclic tertiary base as for example trimethylamine, triethylamine, N-methylpiperidine and the like. Z represents a linking structure which may be either a valence bond, a saturated or unsaturated carbon chain or a heterogeneous chain composed predominantly of carbon. It may be a cyclocarbon such as cyclohexylene or phenylene, a chain including phenylene, cyclohexylene, or some other radical or a chain having simple alkyl substituents thereon such as methyl, ethyl, propyl, butyl and the like. The linking structure is most conveniently (CH where a n equals 1-10.

Where a bifunctional amine is used in preparing the hardener, for example, N,N'-dimethylpiperazine, or where the nitrogen residue is derived from 1,4-diazabicyclo [2.2.2]oetane, polymeric salts Will be formed having good hardening activity. The following recurring structure represents polymers of this nature which are useful as hardeners in accordance with our invention:

In this structure Z and X represent substituents as listed above and n represents the degree of polymerization, being a number from 2 to 20 or even more. R and R are hydrogen or lower alkyl or together they may form the hydrocarbon portion of a ring.

In using the hardeners in accordance with our invention they may be employed in gelatin compositions either where gelatin is the main substituent or in compositions in which gelatin is a carrier for suspended material such as in gelatin-silver halide photographic emulsions, gelatinbarium sulfate compositions or other cases where some pigment or insoluble material is in suspension in the gelatin. Useful compositions are also prepared by incorporating these hardeners into solutions or emulsions of polymers containing carboxyl groups as for example acrylic acid copolymers. These hardeners are conveniently used in proportions of 0.5-5%, based on the weight of the gelatin or other polymer to be hardened. However, it is to be understood that the invention is not limited to these proportions as effective amounts outside of this range may occasionally be employed.

The following examples illustrate the preparation of hardeners useful in accordance with our invention.

EXAMPLE 1 Adipoylbis(N-oxymethylpyridinium perchlorate) 4.86 grams of bis(chlormethyl) adipate were dissolved in 25 ml. of dry pyridine and the solution was heated on a steam bath for 2 hours. The precipitate was isolated and converted to the perchlorate by a double decomposition reaction with sodium perchlorate. Recrystallization from water gave colorless crystals, M.P. 206-207 (corn).

EXAMPLE 2 Adipoylbis (N-oxymethyl-4-picolinium perchlorate) This compound was prepared in the same manner as described in Example 1 except that 'y-picoline was substituted for the pyridine. The melting point of the crystals obtained was 123-125 (corr.).

EXAMPLE 3 Adipoylbis (N-alpha-oxyethylpyridinum perchlorate) The method described in Example 1 was followed except that an equivalent amount of bis(alpha-chlorethyl) adipate was substituted for the bis(chloromethyl) adipate. The material obtained had no definite melting point and tended to boil out on recrystallization.

EXAMPLE 4 Sebacoylbis (N-oxymethylpyridinium perchlorate) This material was prepared by the procedure of Example 1 but using an equivalent amount of bis(chloromethyl) 'sebacate therein. The material obtained had a melting point of 168-171 (corn).

EXAMPLE 5 Adipoylbis( 1-oxymethy1-4-azal-azoniabicyclo- [2.2.2] octane chloride) Poly(1,4-diazoniabicyclo[2.2.2]octane-1,4-dimethyl adipate dichloride) A solutiton of equimolar quantities of the reagents of Example 5 in acetonitrile was heated on the steam bath for one hour. The material was purified by repeated dissolution in water and precipitation into acetone.

The salts obtained in the above examples had the following structural formula:

The various substituents in the examples being as follows:

TABLE I.BIS(ALPHA-CARBONYLOXYALKYL QUATERNARY AMMONIUM) SALTS Samples of the compounds prepared by the above examples were added to separate portions of a high-speed silver bromoiodide emulsion which had been panchromatically sensitized with a cyanine dye. Each emulsion sample was coated on a cellulose acetate film support at a coverage of 432 mg. of silver and 980 mg. of gelatin per square foot. A sample of each film coating was exposed on an Eastman 1B sensitometer, processed for five minutes in Kodak DK-50 developer, fixed, washed and dried with the following results:

TABLE II Percent Conc., vertical g./100 g. Rel. swell in Hardener of example of gel speed Gamma Fog water 1 Control. 100 1. 24 0. 10 609 89 1. 18 09 349 87 1. 15 09 214-281 87 1. 07 08 102-256 2 Control.-- 100 1. 13 12 850 1-.- 118 1.17 .14 570 3 107 1. 10 13 360 3 Control--- 100 1.30 16 750 1 97 1. 33 15 700 3 102 1. 27 15 530 6 102 1. 13 17 490 4 Control--- 100 1.27 17 900 3 1. 05 20 370 6 53 93 29 230 5 Control.-- 1. 23 13 860 1 107 1. 30 14 640 3 89 1. 15 13 260 6 Control.-- 100 1. 37 13 731 3 91 1. 13 11 278 6 74 l. 07 11 10 71 97 10 148 EXAMPLE 7 Adipoylbis(oxymethyltrimethylammonium perchlorate) A solution was prepared by dissolving 7.29 grams of bis(chloromethyl)adipate and 45 grams of trimethylamine in 25 ml. of acetonitrile. The solution was stirred for 8 hours under reflux (using a Dry-Ice condenser) following which it was allowed to stand over night at room temperature. The thick slurry which resulted was diluted with ether and the solids were collected. The chloride obtained was dried and then converted to the perchlorate by a double decomposition reaction with sodium perchlorate. The product obtained was recrystallized from water, giving colorless crystals of the above mentioned compounds, M.P. 235236 C.

EXAMPLE 8 Adipoylbis (oxymethyltriethylammonium perchlorate) A solution was prepared of 30 ml. of triethylamine (dried over calcium hydride) and 4.86 grams of bis- (chloromethyl)adipate in 25 ml. of acetonitrile. The solution was stirred for 2 days under anhydrous conditions. The solids which precipitated (triethylamine hydrochloride) were filtered off and discarded. The filtrate was concentrated to remove volatiles and the residual oil obtained was converted to the perchlorate by a double decomposition reaction. Evaporation gave a saturated aqueous solution of the perchlorate which yielded seed crystals by means of which the whole could be recrystallized from methanol with seeding. Colorless crystals of the above mentioned compound were obtained, M.P. 139-141 C.

Samples of the compounds prepared in Examples 7 and 8 were added to separate portions of a high-speed silver bromoiodide emulsion which had been panchromatically sensitized with a cyanine dye. Each emulsion sample was coated on cellulose acetate film support at a coverage of 459 mg. of silver and 1040 mg. of gelatin per square foot. A sample of each film coating and control samples were exposed on an Eastman 1B sensitometer, processed for minutes in Kodak DK-50 developer, fixed. washed, and dried with the following results:

Percent Cone, vertical g./100 g. Rel. swell in Hardener of example of gel speed Gamma Fog water 7. Control. 100 1. 10 11 810 1 100 1. 13 10 410 8 Control- 100 1. 25 12 810 1 106 1. 28 12 460 EXAMPLES 9, 10 AND 11 Hardening amounts of hardeners in accordance with the invention were added to gelatin containing coating composition as indicated below. Each of the compositions was coated on cellulose acetate film support at the rate of 750 mg. (dry weight) of composition per square foot and dried as was also a sample of composition without hardener. The swell in water of each coating was determined with the following results:

Percent swell in water Percent hardener Percent Hardener hardener in of example in gelatin composition 1 H H B-O-ooz-o-o-o-B-2X I ll mll I R o 0 R in which X is an acid anion, each R is selected from the group consisting of hydrogen and the lower alkyl radicals, Z is a linking structure containing 1-10 carbon atoms selected from the group consisting of saturated carbon chains, unsaturated carbon chains and the heterogeneous chains composed predominantly of carbon and B+ is a quaternary nitrogen residue selected from the following bases, pyridine, a (low carbon alkyl)pyridine, a benzylpyridine and a (low carbon hydroxyalkyDpyridine, the compounds with tertiary nitrogen in the bridgehead position and the aliphatic and cyclic tertiary nitrogen bases and n1 is 0 or 1.

2. A silver halide photographic emulsion in accordance with claim 1 wherein the gelatin-containing vehicle consists essentially of gelatin.

3. A silver halide photographic emulsion in accordance with claim 1 wherein m is 1 and .Z is a straight chain alkylene radical having 1-10 carbon atoms.

4. A silver halide photographic emulsion in accordance with claim 1 wherein the gelatin-containing vehicle consists essentially of gelatin, m' is 1 and Z is a straight chain alkylene radical having 1-10 carbon atoms.

5. A silver halide photographic emulsion in accordance with claim 1 having a gelatin-containing vehicle containing an effective hardening amount of a hardener selected from those consisting of adipoylbis(N-oxymethylpyridium acid anion), adipoylbis(N-oxymethyl-4-picolinium acid anion), adipoylbis(N alpha oxyethylpyridinium acid anion), sebacoylbis(N oxymethylpyridinium acid anion), adipoylbis(l oxymethyl 4-aza-1-azoniabicyclo [2.2.2]octane acid anion), poly( 1,4 diazoniabicyclo [2.2.2]octane-1,4-dimethyladipate acid anion) and adipoylbis(oxymethyltrimethylammonium acid anion).

6. A silver halide photographic emulsion in accordance with claim 2 containing an eifective hardening amount of a hardener selected from those consisting of adipoylbis (N-oxymethylpyridinium acid anion), adipoylbis(N-oxymethyl-4-picolinium acid anion), adipoylbis(N alphaoxyethylpyridinium acid anion), sebacoylbis (N-oxymethylpyridinium acid anion), adipoylbis(l-oxymethyl 4- aza-l-azoniabicyclo[2.2.2]octane acid anion), poly(l,4- diazoniabicyclo[2.2.2]octane 1,4 dimethyladipate acid anion) and adipoylbis(oxymethyltrimethylammonium acid anion).

7. A silver halide photographic emulsion in accordance with claim 1 wherein the hardener compound is adipoylbis (N-oxymethylpyridinium perchlorate) 8. A silver halide photographic emulsion in accordance with claim 1 wherein the hardener compound is adipoylbis (N-oxymethyl-4-picolinium perchlorate) 9. A silver halide photographic emulsion in accordance with claim 1 wherein the hardener compound is adipoylbis(N-alphaoxyethylpyridnium perchlorate).

10. A silver halide photographic emulsion in accordance with claim 1 wherein the hardener compound is sebacoylbis(N-oxymethylpyridinium perchlorate).

11. A silver halide photographic emulsion in accordance with claim 1 wherein the hardener compound is adipoylbis( l-oxymethyl 4-aza-1-azoniabicyclo[2.2.2]octane chloride).

12. A silver halide photographic emulsion in accord ance with claim 1 wherein the hardener compound is poly (1,4-diazoniabicyclo[2.2.2]octane 1,4-dirnethyl adipate dichloride).

13. A silver halide photographic emulsion in accordance with claim 1 wherein the hardener compound is adipoylbis(oxymethyltrimethylammonium perchlorate).

References Cited UNITED STATES PATENTS 2,858,329 10/ 1958 Braaten et al. 260-485 3,169,870 2/1965 Knox et a1. 106-125 NORMAN G. TORCHIN, Primary Examiner R. E. FIGHTER, Assistant Examiner US. Cl. X.R. 

